use generator::MarketMultiplier;
use rust_decimal::Decimal;
use tokio::sync::{Mutex, MutexGuard};

mod generator;

pub(crate) struct Market {
    generator: Mutex<MarketMultiplier>,
}

impl Market {
    pub(crate) fn new() -> Self {
        Self {
            generator: Mutex::new(MarketMultiplier::new(
                Decimal::new(1, 1),
                Decimal::new(1, 0),
            )),
        }
    }

    pub(crate) async fn lock(&self) -> LockedMarket<'_> {
        LockedMarket(self.generator.lock().await, 0)
    }
}

pub(crate) struct LockedMarket<'a>(MutexGuard<'a, MarketMultiplier>, usize);

impl<'a> LockedMarket<'a> {
    pub(crate) fn peek_price(&mut self, initial_price: &Decimal, n: usize) -> Decimal {
        let mut price = *initial_price;
        for i in self.0.peek_n(n).iter() {
            price *= i.modifier();
        }
        self.1 = n;
        price.round_dp(2)
    }

    pub(crate) fn commit(mut self) {
        self.0.next_n(self.1);
    }
}